[Bpoe]

Summary

• Add dscpkg discover [--packages-dir DIR], reusing package-store enumeration to emit sorted, deduplicated JSON Lines containing absolute manifestPath values. Recognize JSON/YAML/YML resources, adapted resources and manifest lists. Discovery is read-only, local-only, ignores inherited DSC_RESOURCE_PATH, and does not contact repositories.
• Record the installed archive's exact OS/architecture in a dscpkg-owned sidecar outside the verified package contents. Advertise only matching platforms; exclude legacy packages with actionable migration diagnostics; reject corrupt provenance and known incompatible cache reuse. Preserve shared package storage, registrations and cleanup behavior.
• Ship the official-schema DscPkg/Discover extension beside the executable in archives, MSI, DEB and RPM. Extend payload/lifecycle checks for registration through DSC, repair, stale-manifest upgrade replacement, uninstall and preservation of user data.
• Document manual installation, per-user/custom stores, service identities, platform/legacy behavior, and the one-time extension-directory bootstrap needed when DSC_RESOURCE_PATH is explicitly set.
• Add unit/process coverage and isolated integration tests pinned to DSC 3.3.0, wired into the platform CI matrix.

Validation

Hosted PR CI passed on the final commit c715314: CI run 40370016665.

• Linux AMD64 and ARM64, Windows, and macOS validation jobs all passed.
• Formatting, vetting, unit tests (with race detection on Linux/macOS), builds, and release safeguard checks passed.
• Official bundled extension manifest schema validation and DSC 3.3.0 integration passed across the matrix: extension discovery through PATH, installation through the CLI into isolated default stores, JSON/YAML resources sharing one executable, invocation from the original package directory, incompatible-platform exclusion, fresh-process discovery, and explicit resource-path bootstrap.
• Native MSI builds/inspection and installation, missing-manifest repair, upgrade replacement of a stale manifest, downgrade rejection, uninstall, PATH handling and user-data retention all passed on disposable Windows runners.
• Linux archive/DEB/RPM builds, inspection, fresh installation, missing-manifest reinstallation, stale-manifest upgrade replacement, uninstall, DSC extension registration and user-data retention passed on AMD64/ARM64 Ubuntu and Fedora test environments.

Additional local validation passed on Windows/Linux, including non-root Linux race tests, workflow/shell linting, and:

Real Linux acceptance case: installed DscExtras.Linux/groups@0.0.1 from https://bpoe.github.io/dsc-extras/ into an isolated store. DSC 3.3.0 listed both groups and services from the single dscextras/linux/0.0.1/dsclinux package and successfully performed read-only gets for root and systemd-journald.service, with DSC_RESOURCE_PATH unset. No existing DSC installation or system package store was changed.

The workstation's MSI build was blocked by its ICE validation policy (WIX1105); validation was not bypassed. The full MSI build and lifecycle subsequently passed on hosted CI. Initial hosted failures in test-fixture permission restoration and Windows cross-drive relative paths were fixed in c715314; the final matrix is green.